1. Field of the Invention
This invention refers to the display of sets of two- or three-dimensional data and, more particularly, to a display system capable of providing precise magnitude information in all dimensions.
2. Description of the Prior Art
Display systems are used in various arts in the analysis of sets of two- or three-dimensional data both for visually detecting particular patterns and for obtaining magnitude information on the data.
In particular, display systems are used in the spectral analysis of complex waves as produced, for example, by a heartbeat or by a human voice, for the purpose of diagnosis or, respectively, recognition. When the complex wave is considered at a fixed instant of time, the analysis involves only two dimensions, namely, frequency and amplitude; while when the variations of wave with the time are also considered, the analysis involves three dimensions, namely, frequency, amplitude and time.
Various systems have been developed to display two- or three-dimensional data in order to give a synoptic image of the phenomenon to be analyzed. With particular reference to the spectral analysis, one prior art system consists of plotting a diagram in cartesian orthogonal coordinates with the time on the horizontal axis, the frequency on the vertical axis, and the relative amplitude of the spectrum components shown in terms of the darkness of the points of the diagram. Another prior art system consists of plotting a diagram in orthogonal coordinates with the time on the horizontal axis and the frequency on the vertical axis, the relative amplitude of each spectrum component being shown as a small deflection of the diagram in the direction of the horizontal axis. However, neither of such prior art systems provides precise magnitude information.